Sometimes it can help to find a fabric you really like that has the colors you want in your quilt all in that one fabric. Then, find fabrics that look good with the fabric you chose first, trying to get a combination of scales of prints, tone on tones, solid if you like them, once you have a nice pile, sometimes you can even take away the original fabric you started with and still have a group of fabrics that work together well for a quilt, or you can keep the "theme" fabric to use in the quilt, and it probably would be a great fabric to use for the border.
Good luck!!